Cooling and Enhanced Sea Ice Production in the Ross Sea Josefino C. Comiso, NASA/GSFC, Code The Antarctic sea cover has been increasing at 2.0% per decade, while the Arctic ice cover has been declining at - 4.4% per decade. Increases in the Antarctic ice area have been attributed, through modeling studies, to the ozone hole which caused a deepening of the Amundsen low, stronger winds and therefore more ice production in the Ross Sea. Satellite studies confirm cooling and an enhanced ice production in the Ross Sea region. Ice Production Fig. 1: Trends in sea ice concentration in winter, spring, summer and autumn. Fig. 2: Trend in surface temperature from August 1981 to July Fig. 3: Ice production in the Ross Sea from 1992 to 2007 as inferred from latent heat polynya formations in the region Hydrospheric and Biospheric Sciences Laboratory

Name: Josefino C. Comiso, NASA/GSFC, Code Phone: References: Comiso, J. C., R. Kwok, and S. Martin (submitted, 2009) Variability and trends in sea ice and ice production in the Ross Sea, Deep Sea Research. Turner, J., J.C. Comiso, G. J. Marshall, W.M. Connolley, T.A. Lachlan-Cope, T. Bracegirdle, Z. Wang, M. Meredith and T. Maksym, (2009) Antarctic sea ice extent increases as a result of anthropogenic activity, Geophy. Res. Lett. 36, L08502, doi: /2009GL Comiso, J.C., (2000) Variability and trends in Antarctic surface temperatures from in situ and satellite infrared measurements, J. Climate, 13(10), , Data Sources: Nimbus-7 SMMR ice concentration data from November 1978 to July 1987 and DMSP-SSM/I ice data from August 1987 to the present. NOAA/AVHRR surface temperature data From August 1981 to July 2008 Technical Description of the Images: Fig. 1 Trends in sea ice concentration in winter, spring, summer and autumn. Ice concentration is shown to be increasing (in green color) in the Ross Sea and other regions while that for the Bellingshausen/Amundsen Seas is declining. Fig. 2 Trend in surface temperature from August 1981 to July Cooling is indicated in the Ross Sea (gray and green areas) and parts of Antarctica while warming is observed at the Bellingshausen/Amundsen Seas. Fig. 3 Ice production in the Ross Sea from 1992 to 2007 as inferred from latent heat polynya formations in the region. Scientific Significance: It has been intriguing that the Antarctic sea ice cover is increasing at 2% per decade while the Arctic perennial ice is declining at a rapid rate of %/decade. Stronger winds in the region due to the effect of the ozone hole as inferred from recent modeling studies have been confirmed in a new study that reveals ice production increases in polynya regions in the Ross Sea. Relevance to future science and relationship to Decadal Survey: The study demonstrates the importance of long term satellite climate data sets to confirm modeling predictions of changes in the climate and environment and especially those associated with anthropogenic activities. This new insights into a seemingly improbable scenario of increasing ice cover and some cooling in the Antarctic could lead to a better understanding of processes in the Antarctic region and how global climate change is reflected in the region. Hydrospheric and Biospheric Sciences Laboratory

Advective Time Scale for Surface Salinity David Adamec, NASA GSFC, Code A numerical stability analysis was conducted to calculate the characteristic time scale of the surface salinity field for the Pacific Ocean. Due to accuracy requirements, NASA’s Aquarius instrument will return surface salinity products every 30 days. Figure 1: Advective time scale for surface salinity as determined from 23-year model simulation of the North Pacific forced by momentum and buoyancy fluxes from NCEP analysis fields. Hydrospheric and Biospheric Sciences Laboratory

References: Li, Z., and D. Adamec, 2009: Assessing the Potential to Derive Air-Sea Freshwater Fluxes from Aquarius-like Observations of Surface Salinity, Int. J. Remote Sensing, in press. Data Sources: Surface momentum and buoyancy fluxes from NCEP analyses. Technical Description of the Images: Fig. 1 Over much of the Pacific, that temporal resolution may be sufficient to estimate local exchanges of fresh water between the atmosphere and the ocean. However, in areas that are colored blue, particularly along the equator, and near the western boundaries of the Pacific, the strong surface currents evolve the salinity fields more quickly than the resolution of the satellite products, thus, much more complex methods than a simple local balance between salinity changes and fresh water exchange with the atmosphere will be necessary to characterize the processes associated with the salinity variability there. In areas with light green shading, the effects of advection and local processes are about the same over the repeat time of the satellite observation, and there too, extreme care will need to be taken inferring local balances and processes from salinity changes. Scientific Significance: Simulations indicate that one of the scientific goals of Aquarius, determining air-sea fresh water exchanges from temporal changes in salinity may be limited geographically away from the equator, and western boundary current regimes. Relevance to future science and relationship to Decadal Survey: There is direct relevance to Aquarius mission science. The lack of reliable estimates of fresh water exchanges over the Pacific equatorial regime may have impacts for future characterization and prediction of ENSO variability. Name: David Adamec, NASA GSFC, Code Phone: Hydrospheric and Biospheric Sciences Laboratory